From today the maximum sentence for anyone caught carrying a knife on the streets of Northern Ireland will double to four years in prison.

The Government is rolling out a series of tough measures against violent crime as concern across the UK about lethal blades reaches an all-time high.

The new powers for courts are also targeting sex offenders who breach their licences while living in the community and dangerous drivers who kill.

The criminal justice reforms which become active today include:

Powers relating to offences involving knives and other offensive weapons are increased, with maximum sentences increased to four years imprisonment and/or an unlimited fine for having a knife or an offensive weapon in a public place or on school premises. There will also be new offences relating to the sale or unlawful marketing of knives, including sale of knives to persons under 18 years of age.

There will also now be a presumption in favour of prosecution for possession of a knife.

Breach of sex offender licences, which could only be dealt with by the Magistrates Court and carried a maximum penalty of six months, can now be referred directly to the Crown Court when the offender was originally sentenced there. The Crown Court will have the power to revoke the licence completely with the result that the offender will then serve the remainder of the license period in custody.

Road traffic powers are also strengthened through the creation of a number of new offences, including causing death or grievous bodily injury by careless or inconsiderate driving; and through increased penalties for driving without insurance, while disqualified or for failing to stop for police. There are also new police powers around breath specimens and revised definition of driving without due care and attention.

In Northern Ireland there have been a number of incidents involving knives.

Last week Shane Cunningham was found stabbed at a house in Woodbreda Park in Belfast, and last month Bangor guesthouse owner Billy Spence was stabbed to death in his own home.

The Government also intends to set up a retail licensing scheme and a test purchase scheme to ensure that knives are not being sold to anyone under the age of 18.

Criminal Justice Minister Paul Goggins said: "These new powers send out a clear message that society will not tolerate those who continue to break the law and make life intolerable for their communities.

"The introduction and commencement of these new powers will strengthen and enhance public protection arrangements," he said.

"I am only too well aware of the horrendous outcomes for those who suffer the violence of knife crime. Whilst the level of knife crime in Northern Ireland is not as high as it is in other parts of the UK, the harm caused to victims and their families can be devastating, so we should all work together to make it clear that carrying a knife is against the law, carries stiff penalties and could be lethal. People who carry knives put themselves and others at risk of serious injury."

Mr Goggins added: "I welcome the recent agreement between the PSNI and the Public Prosecution Service that people who carry knives put themselves, as well as others, at serious risk of injury and those caught in possession of a knife in a public place with no reasonable excuse or who use a knife to commit an offence can expect to be prosecuted.

"The relaunch of the PSNI's knife campaign scheduled for early next week will again raise awareness and reinforce the key messages on this issue.

"In addition I have asked the Prison Service, the Probation Board and the Youth Justice Agency to evaluate what further interventions with young people might contribute to a reduction in knife crime," he added.